Elastic Properties of Aligned Carbon Nanotube Polymer Nanocomposites with Controlled Morphology

Handlin, Daniel; Villoria, Roberto Guzmán de; Chan, Shiau Wei; Takahashi, Kosuke; Cebeci, Hülya; Williams, Marcel R.; Parsons, Ethan M.; Socrate, Simona; Wardle, Brian L.

doi:10.2514/6.2012-1565

Cited by 3 publications

(2 citation statements)

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“…Results are presented in Figure 4.1 and As has been previously discussed 11,12 , the A-PNC modulus is far from that predicted in a simple rule of mixtures analysis for collimated CNTs in a matrix: e.g., for 20% volume fraction aligned CNTs with a MWNT fiber modulus of 0.5 TPa, the composite modulus is expected to be ~60 GPa, rather than ~6 GPa measured here. Similar behavior has been observed in testing via nano-indentation for the A-PNC system studied here.…”

Section: Discussion Of Optical Strain Resultsmentioning

confidence: 89%

“…However, to date, the full three-dimensional constitutive relations of A-CNTs in an aerospace grade structural epoxy have not been reported. This study reports on efforts to develop these relations by use of these previously reported fabrication techniques in conjunction with digital image correlation (DIC), also known as optical strain mapping, thereby building upon previously reported work 12 .…”

Section: Overviewmentioning

confidence: 99%

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Three-Dimensional Constitutive Relations of Aligned Carbon Nanotube Polymer Nanocomposites

Handlin

2013

54th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference

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Variable and high volume fraction aligned carbon nanotube (CNT) polymer nanocomposites (A-PNCs) are fabricated by biaxial mechanical densification of the CNTs, followed by polymer infiltration via capillarity-assisted wetting using an aerospace-grade epoxy. These APNCs are mechanically tested in order to determine the full elastic constitutive relations of the material as a function of volume fraction. Prior to this work, only bulk compression or nanomechanical tests have been attempted due to the small size of the samples. Elastic stiffness results derived from optical strain mapping via digital image correlation are in agreement both with prior experimental nanoindentation measurements and finite element calculations that include the effects of waviness of the reinforcing CNT 'fibers'. Results from longitudinal, transverse, and shear directed testing are shown for 0 to ~20% volume fraction aligned CNT reinforcement. Imaging via scanning electron microscopy and micro-computed tomography is used to establish morphology for structure-property relations. These are the first full elastic constitutive relations for non-isotropic aligned-CNT PNCs. Such relations are needed for modeling and understanding hierarchical nanoengineered composite architectures. Recommended future work includes more comprehensive shear sample testing and concerted modeling efforts to relate this experimental work to computational/theoretical studies of the nanocomposite properties as a function of morphology. AcknowledgementsI have received a great deal of help from many individuals without whom it would not have been possible to complete this thesis.First and foremost, my advisor Professor Brian Wardle has been a fantastic mentor from day one at MIT. He is always available to answer my numerous questions and many times throughout my project offered a new avenue to explore when I felt like I had run into a wall with one approach or another. From familiarizing me with the literature and teaching me the methodology and mindset of a successful researcher and scientist, this project could not have been completed without his guidance.My colleagues in necstlab have been enormously helpful throughout my experiences. Sunny Wicks was always happy to share her enormous expertise in all aspects of the research process, whether dealing with curing epoxy, growing and densifying CNT forests, or more mundane matters like which classes to take or which of the bewildering array of forms at MIT actually need to be filled out. Ethan Parsons provided incalculable help in the aspects of digital image correlation and testing, and taught me a great deal about the mindset of a good scientist. He introduced me to the DIC literature and taught me to use Vic-2D as software that performs digital image correlation rather than a program where I press some buttons and hope that a black box process gives me a logical answer. He also helped to show me the importance of attention to detail-making sure that cameras are parallel to the ground, not 5 degrees from para...

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Section: Discussion Of Optical Strain Resultsmentioning

confidence: 89%

Section: Overviewmentioning

confidence: 99%